Despite the stunning departure of reigning champion Chris Froome in a crash the day before, the Italian says he's "afraid" of two-time champ Alberto Contador, and senses other contenders are looking for opportunities to strip him of cycling's most coveted jersey.

Nibali took another, if small, step on Thursday toward the Tour crown by maintaining his lead as the pack arrived in Reims — whose famed Cathedral hosted many French coronations — in a drizzly and crash-marred sixth stage won by German sprint specialist Andre Greipel.

Nibali, who has won cycling's two other Grand tours — the Spanish Vuelta and Italian Giro — made it five straight days in the yellow shirt that he hopes to take home when the race ends on the' Champs-Elysees on July 27.

It's still very early, though, and the race has only had one real climbing day so far: Far tougher up-and-down days are ahead this weekend in the Vosges mountains, in the Alps in week two, and the Pyrenees in week three.

But Nibali says he is "calm" and feeling good physically, his Astana team is the best-performing squad so far, and several rival teams have been losing riders to crashes.

"I'm still afraid of Contador," said Nibali, adding that he expects the Spaniard and other yellow jersey aspirants to attack when the race enters the eastern Vosges range on Saturday — culminating with a tough uphill finish in Monday's Stage 10.

"It's true that you can lose a lot of energy defending the yellow jersey, but I've been riding well," Nibali said through a translator. "It's a heavy task to wear it ... (but) to have the jersey could be a little advantage in the coming stages. We'll take it day by day."

Contador, a day after losing about 2 1/2 minutes to Nibali on a muddy ride over cobblestones, was dealt another setback on Thursday: His Saxo-Tinkoff teammate Jesus Hernandez, who was expected to help him up the climbs, dropped out after a crash that left him dazed on the roadside.

Richie Porte, who inherited the leadership of Team Sky after Froome quit, also lost a teammate. Spanish veteran Xabier Zandio was taken to hospital with a suspected broken rib and severe back injury from a group spill with about 79 kilometers left.

The race medical report listed a total of 14 riders with varying injuries from "two big crashes."

"It was such a stressful day — horrible actually," Porte said, crediting support from his team. "The guys were around me all day, and while we lost Xabi Zandio to the crash, the rest of us kept out of trouble and we live to fight another day."

Greipel, the Germany champion, collected his sixth career Tour stage win ahead of Norway's Alexander Kristoff in second and France's Samuel Dumoulin in third over the 194-kilometer (120-mile) ride. Greipel's job got easier after countryman Marcel Kittel, who has dominated the sprints this year, got a late flat.

The top of the standings didn't change, as most of the contenders for victory in the three-week race trailed close behind the muscular Greipel. He was not a challenger for the overall title; like many sprinters, he does not fare well on the climbs that are crucial to winning in Paris. He's 37 1/2 minutes behind Nibali.